Barack Obama was born on August 4, 1961 in Honolulu, Hawaii. His father came to America from Kenya, which is a country in Africa. His parents, Ann and Barack, met when they were students at the University of Hawaii. Since Barack had the same name as his father, young Barack went by the nickname “Barry”.

    In 1979, after he finished high school, Barry went to Occidental College in Los Angeles, California. There, he started to learn about his African roots and decided to use his African name, Barack. After two years in L.A., he went to Columbia University in New York City to study politics.

    After college, he moved to Chicago, Illinois, where he worked to help poor people in his city. He traveled to Africa to meet his grandmother and cousins for the first time. He went back many times over the years to visit with his family and learn about where he came from. At work, he met a lawyer named Michelle Robinson. They worked together in a big law firm. Then he left Chicago to go to Harvard Law School in Cambridge, Massachusetts. He did very well in law school.

    After he was done with school, Barack moved back to Chicago and in 1992 he married Michelle. He worked as a lawyer, devoted to helping poor people for free who had been treated unfairly. He worked hard to get the people he helped to vote.

    He made many people believe that their votes were important, and helped them feel like they could make a difference.

    Electrical devices (仪器) could soon use power made by human energy. Scientists say they have developed an experimental device that produces electricity from the physical movement of a person walking. British scientist Max Donelan and other scientists in Canada and the United States developed the device.

    The device connects to a person's knee. As the person walks, the device captures energy each time the person slows down. To do this, the device helps with the slowing down movement of the leg. The movements of the walking person push parts of a small machine that produces electricity. Using the device, an adult walking quickly could produce thirteen watts of electricity in just a minute. Donelan says walking at that speed could produce enough power to operate a laptop computer for six minutes.

    There are several possible uses for the device. Developers say it could help people who work in areas without electricity to operate small computers. The device could also be used in hospitals to operate heart pacemakers (起搏器). It could even be used to assist in the movement of robotic arms and legs.

    The experimental version of the device weighs about one and a half kilograms, but it is too costly for most people to buy. But the researchers hope to make a lighter, less costly version. An improved version should be ready in one year.

    The developers hope the device will one day help developing countries. Nearly twenty-five percent of people around the world live without electric power.

    A similar product was invented in 2005 by Larry Rome of the University of Pennsylvania. He created a bag carried on a person's back that also produces power from walking. The knee device does not produce as much electricity as the bag. But the bag requires the walker to carry a load of twenty to thirty kilograms.

    Rent control, like all other government-mandated（强制执行的）PRICE CONTROL,is a law placing a maximum price, or a "rent ceiling," on what landlords may charge tenants（房客）.It is a program designed to stop rents from rising rapidly and is used mainly in large urban areas where there are more people than housing. In cities with rent control, the city government sets the maximum rent that a landlord can charge for an apartment. Supporters of rent control argue that it protects people who are living in the apartments. Their rent cannot increase; therefore, they are not in danger of losing their homes. However, almost all the critics conclude that rent control is destructive. They say after a long time, rent control may have negative effects.

    In a 1990 survey of 464 people published in the May 1992 issue of the American Economic Review,93% of US respondents agreed that a ceiling on rents reduces the quantity and quality of apartments available. Landlords are too cautious (perhaps too smart) to put their faith in rental apartments because they know that the rental-controlled apartments cannot increase their profits. Therefore, they invest in other businesses where they can increase their profits. They do not invest in new buildings which would also be rent-controlled. As a result, new apartments are not built. Many people who need apartments cannot find any.

    Some theorists argue that the minimum wage law can cause problems in the same way. The federal government sets the minimum that an employer must pay workers. The minimum helps people who generally look for unskilled, low-paying jobs. However, if the minimum is high, employers may hire fewer workers. They will replace workers with machinery. The price, which is the wage that employers must pay, increases. Therefore, other things being equal, the number of workers that employers want decreases. Thus, critics claim, an increase in the minimum wage may cause unemployment. Some poor people may find themselves without jobs instead of with jobs at the minimum wage.

    Supporters of the minimum wage say that it helps people keep their dignity, Because of the law, workers cannot sell their services for less than the minimum. Furthermore, employers cannot force workers to accept jobs at unfair wages.But the supporters make a big error. They fail to realize that it is possible for such a law to increase wages beyond the value of what the workers contributes.

    Economic theories predict the results of economic decisions such as decisions about farm production, rent control, and the minimum wage. The predictions may be correct only if "other things are equal". Economists do not agree on some of the predictions. They also do not agree on the value of different decisions. Some economists support a particular decision while others criticize it. Economists do agree, however, that there are no simple answers to economic questions.

    Just like rice and noodles are different from bread, snacks in China are a world apart from those in the UK and the US. For one thing, I never imagined that sunflower seeds (瓜子) would be so popular here. I spotted people having them while waiting for tables outside restaurants, before dinner and, of course, while watching TV. I also saw that a plate of sunflower seeds is always on offer during the Spring Festival holidays.

    I had seldom tried sunflower seeds when I came to China. In the UK, though, young people love their snacks. In fact, young people in Britain eat more snacks than people of the same age in other European countries. A recent survey has discovered that 64 percent of under 20-year-olds snack between meals, according to an article on the British Council website. In comparison (对比), 58.7 percent of young people snack in Germany, 53 percent in France, and only 40.7 percent in Spain.

    British snacks are generally unhealthy. Our favorites are probably potato chips, which we call crisps, and chocolate bars. From a very young age, we always looked forward to our crisps and chocolate bars after school, perhaps even included with sandwiches and fruit in our school lunches that our parents made for us.

    Snacks are also popular in the US. One of the things that I found the most extraordinary when I first visited the US was the number of snacks in their supermarkets; I was surprised to find huge aisles (过道) just for snacks that were bigger than some stores I'd been to in the UK. Snack tastes in the US are much the same as those in the UK, except there's much more choice – every kind of fatty, sugary food is available (可获得的) to everyone all the time.

    All in all, it's probably best for your health if you like sunflower seeds rather than potato chips and chocolate. But eating these delicious treats at times couldn't possibly be wrong, could it?

    A valuable sketch (素描) from World WarⅠhas turned up in a garage sale in Perth. It's a sketch of soldiers playing soccer with a tin can during an unofficial truce (停战) between German and Allied soldiers on the Western Front in 1914. The artwork was drawn by an unnamed German soldier during the war on the Western Front.

    The artwork was given to Private Jack Shelley, a British soldier, when he was defending the town of Frelinghien, France. The sketch is an important historical document, as it provides evidence that the tales of enemy soldiers socializing together are true. But for Private Shelley's descendants(后代) it has even greater value, since it was his prized possession. Jessie Shelley, Jack's great-granddaughter, has fond memories of the old man sharing stories about his experiences in the war when he came to live permanently in Australia in 1930, the family lost track of the artwork after Jack's possessions were moved during the sale of his house when he died in 1984.

    ‘Great-grandpa had a tobacco tin with a dozen or so buttons from the uniforms of men from both sides. He told us all the details of every one of those buttons. To Great-grandpa they represented real people he had known, some of whom hadn't come home from the war. He had at least two buttons from German uniforms that he told us were exchanged between the men involved in the Christmas Day Truce.'

    On Christmas Day of 1914, the soldiers came out of their trenches(战壕) into no-man's-land and shared food, drinks and cigarettes. Some even exchanged small gifts. The men even played football games together. Later, this spirit of cooperation continued in unofficial agreements between the sides to stop shooting at mealtimes and even at times when soldiers were working in the open.

    This fascinating image of peace and humanity during the war has continued through the years. The sketch is a symbol of the potential for humanity, hope and kindness to exist in even the most violent circumstances.

    A day in the life of 18-year-old David Lanster is full of teenage activities: school, baseball practice, homework. And then he starts cooking. "Some nights I'm up until 1 a.m. making pies, or even later if we're cooking beef," said the student at Ransom Everglades High School in Florida, US.

    For the past year, Lanster and Kelly Moran, his classmate, have been hosting fancy dinner parties at Lanster's parents' home. Their meals have 17 courses and are all made by them. Their guests used to give them gifts to thank them, until the pair decided to do something nice for charity. "We got some really great Miami Heat tickets, a nice watch, and many kitchen machines," Lanster said. "But we wanted to make this something positive for people rather than us."

    Lanster and Moran focused on Common Threads, a charity(慈善机构) that helps to teach kids in poor neighborhood to cook and make healthy eating choices. The young cooks ask their guests to give however much they want as payment for their meals. It all goes to Common Threads because Lanster's parents cover their food costs. After their last 12-person event, Lanster and Moran gave $1,600 to the charity. Now, they're taking their show out of the kitchen and on the road. Lanster and Moran have started to organize private dinner parties in a similar way: the host pays for the ingredients(食材), and the guests make a donation (捐赠) to a charity.

    Outside the kitchen, the two are busy preparing their college applications. Neither is sure what they will do in the future, but they've promised their parents that they'll leave cooking alone until they finish high school.